JP2001272700A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device using a homogeneous alignment method, in which good display quality can be maintained without causing irregular alignment in the homogeneous alignment state of the liquid crystal molecules. SOLUTION: The liquid crystal layer of the liquid crystal device 1 is formed into such a structure that the liquid crystal molecules of a nematic liquid crystal with addition of a chiral agent are homogeneously aligned. Thereby, irregular alignment in the homogeneous alignment state of the liquid crystal molecules is prevented by not only the stability in the homogeneous alignment of the liquid crystal molecules by the anchoring effect of the alignment films formed on the inner faces of a pair of substrates 2, 3 and by the spontaneous cohesive power of the nematic liquid crystal but also by the effect of the interactive force between the liquid crystal molecules by the chiral agent added to the liquid crystal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display of a homogeneous alignment type.

[0002]

2. Description of the Related Art A homogeneous alignment type liquid crystal display device in which liquid crystal molecules sealed between a pair of substrates are aligned in one direction and initially aligned is compared with a TN (twisted nematic) type liquid crystal display device. Since the arrangement is not twisted, there is an advantage that optical changes due to a change in viewing angle are small, a viewing angle of display is wide, and optical characteristics are easily compensated.

The above-mentioned homogeneous alignment type liquid crystal display device comprises a nematic liquid crystal having a positive dielectric anisotropy formed between a pair of transparent substrates having a transparent electrode on each of opposing inner surfaces and an alignment film formed thereon. The liquid crystal device includes a liquid crystal element in which a liquid crystal layer in which the liquid crystal molecules are homogeneously aligned along one direction is sealed, and a pair of polarizing plates disposed with the liquid crystal element interposed therebetween.

[0004]

However, in the conventional homogeneous alignment type liquid crystal display device, the stability of the alignment for causing the liquid crystal molecules in the liquid crystal layer to be homogeneously aligned is dependent on the anchoring by the alignment film and the spontaneous generation of the nematic liquid crystal. Cohesive force (intermolecular force to align liquid crystal molecules in one direction)
, Alignment unevenness is likely to occur in the homogeneous alignment state of the liquid crystal molecules.

That is, in the liquid crystal molecules of the liquid crystal layer, in the initial alignment state, the major axes of the liquid crystal molecules are not uniformly arranged in one direction, and alignment unevenness is likely to occur, and the liquid crystal molecules are applied between electrodes of a pair of substrates. The orientation changes according to the electric field so that it rises with respect to the substrate surface.However, after the liquid crystal molecules behave largely, when the electric field is cut off, the directors of the liquid crystal molecules are aligned in one direction and become a homogeneous homogeneous orientation. It does not return, causing uneven alignment.

Further, for example, when the substrate of the liquid crystal element is bent and deformed by an external pressing force and the orientation state of the liquid crystal molecules in that region is largely disturbed, the director of the liquid crystal molecules is restored even if the bent deformation of the substrate is restored. Uniform homogeneous alignment in one direction does not occur, and alignment unevenness occurs.

As described above, the conventional homogeneous alignment type liquid crystal display device has a problem that alignment unevenness is apt to occur in the homogeneous alignment state of liquid crystal molecules, and display defects occur in the region.

An object of the present invention is to provide a homogeneous alignment type liquid crystal display device which can maintain good display quality without causing alignment unevenness in a homogeneous alignment state of liquid crystal molecules. Things.

[0009]

According to the present invention, there is provided a liquid crystal display device comprising: a pair of substrates on each of which opposing inner surfaces are provided with an electrode and an alignment film covering the electrodes; A liquid crystal layer in which liquid crystal molecules of a nematic liquid crystal to which a chiral agent is added are homogeneously aligned along one direction, and a polarizing plate disposed on at least a display observation side of the pair of substrates. It is assumed that.

This liquid crystal display device has a liquid crystal layer in which a nematic liquid crystal to which a chiral agent is added is aligned in a homogeneous state in which the liquid crystal molecules are directed in one direction. In addition to the anchoring by the film and the spontaneous cohesive force of the nematic liquid crystal, an intermolecular force acting between liquid crystal molecules acts due to the chiral agent added to the liquid crystal.

Therefore, according to this liquid crystal display device, the stability of alignment of liquid crystal molecules is improved, and uniform homogeneous alignment in which directors of liquid crystal molecules are arranged in one direction can be obtained.
Then, even when the behavior of the liquid crystal molecules due to the electric field or the alignment state of the liquid crystal molecules is disturbed due to the bending deformation of the substrate of the liquid crystal element, the director then returns to the homogeneous alignment in which the directors are aligned in one direction. Therefore, there is no occurrence of alignment unevenness in the homogeneous alignment state of the liquid crystal molecules, and good display quality can be maintained.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, in the liquid crystal display device of the present invention, the liquid crystal layer of the liquid crystal element is formed into a uniform homogeneous alignment in which directors align liquid crystal molecules of a nematic liquid crystal to which a chiral agent is added in one direction. With this configuration, it is possible to prevent the occurrence of alignment unevenness in the homogeneous alignment state of the liquid crystal molecules and to maintain good display quality.

In the liquid crystal display device according to the present invention, the amount of the chiral agent to be added is determined by the thickness d of the liquid crystal layer of the liquid crystal element.
The ratio d / p between (μm) and the natural pitch p (μm) of the nematic liquid crystal to which the chiral agent has been added may be an amount that is less than 0.09. Thereby, it is possible to obtain a uniform homogeneous alignment initial alignment state in which the directors are aligned in one direction without twisting the liquid crystal molecules.

[0014] The amount of the chiral agent added is d / p
Is more preferably 0.075 or less,
This makes it possible to set the initial alignment state of the liquid crystal molecules to a homogeneous alignment with higher stability.

[0015]

FIG. 1 is an exploded perspective view of a part of a liquid crystal display device according to an embodiment of the present invention.

The liquid crystal display device of this embodiment is of a reflection / transmission type which performs a reflection display using external light which is light of the use environment and a transmission display using illumination light from behind. The liquid crystal display device includes a liquid crystal element 1, a pair of front and rear polarizers 14 and 15 disposed with the liquid crystal element 1 interposed therebetween, and a reflection / illumination unit 16 disposed behind the rear polarizer 15.

The liquid crystal element 1 used in this embodiment is a TFT
(A thin film transistor) is an active matrix liquid crystal element having an active element, which is one of a pair of front and rear transparent substrates 2 and 3 arranged opposite to each other, for example, a substrate on the opposite side to a display observation side. On the inner surface of the rear substrate 3, a plurality of transparent pixel electrodes 4 arranged in the row and column directions, a plurality of TFTs 5 respectively connected to the pixel electrodes 4, and a plurality of TFTs 5 for supplying a gate signal to the TFTs 5 in each row. And a plurality of data lines 12 for supplying data signals to the TFTs 5 in each column, respectively.
And a plurality of compensating capacitance electrodes 13 forming a compensating capacitance between the pixel electrode 4 and the pixel electrode 4.

The TFT 5 has a gate electrode 6 formed on the inner surface of the rear substrate 3, a gate insulating film 7 covering the gate electrode 6, and a gate insulating film 7 facing the gate electrode 6. And a source electrode 9 and a drain electrode 10 formed on both sides of the i-type semiconductor film 8 via an n-type semiconductor film (not shown). .

The gate line 11 is wired on the inner surface of the rear substrate 3 along one side of each pixel electrode row, and the gate electrode 6 of the TFT 5 in each row is connected to the gate corresponding to the row. It is formed integrally with the line 11.

The gate insulating film (transparent film) 7 of the TFT 5 is formed over substantially the entire surface of the rear substrate 3, and the gate line 11 is covered with the gate insulating film 7 except for its terminal. Have been done.

The data line 12 is wired on the gate insulating film 7 along one side of each pixel electrode column, and the drain line 1 of the TFT 5 in each column is provided.
0 is connected to the data line 12 corresponding to the column.

In this embodiment, the data line 12
Are formed on the gate insulating film 7, and the drain electrodes 10 of the TFTs 5 in each column are formed integrally with the data lines 12 corresponding to the respective columns.
Means that the TFT 5 is covered with an interlayer insulating film and wired thereon, and the TFT 5 is inserted into a contact hole provided in the interlayer insulating film.
5 may be connected to the drain electrode 10.

The pixel electrodes 4 are formed on the gate insulating film 7, and the TFs corresponding to the pixel electrodes 4 are respectively formed at one side edge of the pixel electrodes 4.
The source electrode 9 of T5 is connected.

The compensation capacitance electrode 13 is formed on the inner surface of the rear substrate 3 so as to correspond to each of the pixel electrode rows. The gate insulating film 7 therebetween forms a compensation capacitance for compensating the fluctuation of the potential of the pixel electrode 4 during the non-selection period.

The compensation capacitor electrode 13 is provided between a line portion facing one edge of the pixel electrode 4 and the pixel electrodes 4 adjacent to the pixel electrode 4 in the row direction with the data line 12 interposed therebetween. The compensation capacitor is formed in a shape having an extended portion which is extended to a region, and has an extension portion which is opposed to a side edge portion of each of the adjacent pixel electrodes 4 and 4 at both side edge portions. It is formed on three edges, that is, a portion and both side edges.

On the other hand, although not shown, a plurality of color filters, for example, red, green and blue color filters are provided on the inner surface of the other substrate, that is, the front substrate 2 which is a substrate on the display observation side. , And a single film-shaped transparent counter electrode facing the plurality of pixel electrodes 4 is provided thereon.

Although not shown in the drawing, a horizontal alignment film made of polyimide or the like is provided on the innermost surfaces of the pair of substrates 2 and 3, respectively.
By rubbing the film surface in a predetermined direction, orientation treatments are performed substantially parallel to each other and in opposite directions. In the figure, the broken arrow 2a indicates the direction of the alignment treatment applied to the inner surface of the front substrate 2, and the solid arrow 3a indicates the direction of the alignment treatment applied to the inner surface of the rear substrate 3.

The pair of substrates 2 and 3 are joined at their peripheral edges via a frame-shaped sealing material (not shown), and a liquid crystal is formed between the substrates 2 and 3 in a region surrounded by the sealing material. A layer (not shown) is provided.

The liquid crystal layer is composed of a nematic liquid crystal having a positive dielectric anisotropy to which a chiral agent is added, and its liquid crystal molecules are aligned in the vicinity of the front substrate 2 and the rear substrate 3 with the respective substrates 2. , 3 are regulated by the alignment film on the inner surface, and are pretilted at a slight angle with respect to the surfaces of the substrates 2, 3 in one direction (the alignment processing direction 2 of the substrates 2, 3).
a, 3a).

Further, the pair of front and rear polarizing plates 14 and 15 disposed with the liquid crystal element 1 interposed therebetween are provided with their optical axes (transmission axes or absorption axes) directed in predetermined directions.

In the figure, an arrow 14a indicates a front polarizer 14 disposed on the front side, which is the display observation side of the liquid crystal element 1.
The arrow 15a indicates the transmission axis of the rear polarizing plate 15 disposed on the rear side of the liquid crystal element 1, and
In this embodiment, the transmission axis 14a of the front polarizing plate 14 is aligned with the alignment direction 2a of the pair of substrates 2 and 3 of the liquid crystal element 1.
With respect to 3a, it is set in a direction obliquely intersecting at an angle of approximately 45 ° in one direction (in the figure, counterclockwise as viewed from the front side of the liquid crystal element 1), and the transmission axis 15 of the rear polarizing plate 15 is The direction is set so as to intersect the transmission axis 14a of the front polarizing plate 14 at an angle of about 90 °.

On the other hand, the reflecting / illuminating means 16 disposed behind the rear polarizing plate 15 has a light reflecting function and an illuminating light emitting function, and the reflecting / illuminating means used in this embodiment is used. The means 16 includes a surface light source 17 that emits illumination light from the entire front surface, and a transflective film 18 disposed on the front surface of the surface light source 17.

The surface light source 17 is, for example, a transparent light guide plate which takes in light from an end face and emits the light from the entire front face, and a straight tube-shaped fluorescent light source arranged opposite to the end face of the light guide plate. It consists of a lamp.

This liquid crystal display device can be used in a bright environment.
The reflective display using external light is performed. In the case of the reflective display, of the light incident on the liquid crystal display device from the front surface and transmitted through the front polarizing plate 14 and the liquid crystal display element 1,
Light of a polarization component along the transmission axis 16a of the rear polarizing plate 16 passes through the rear polarizing plate 16 to become image light, and the image light is reflected by the transflective film 18 of the reflecting / illuminating means 16, The light passes through the rear polarizer 16, the liquid crystal display element 1, and the front polarizer 14 and is emitted to the front.

In addition, this liquid crystal display device can be used in an environment where external light with sufficient brightness cannot be obtained.
In this transmissive display, the illumination light from the surface light source 17 emits the illumination light from the surface light source 17. 18, rear polarizing plate 16 and liquid crystal display element 1
Is transmitted to the front polarizing plate 14, and of the light, the light of the polarization component along the transmission axis 14a of the front polarizing plate 14 is transmitted through the front polarizing plate 14 to become image light. The light is emitted to the front.

In both the reflective display mode and the transmissive display mode, the liquid crystal molecules in a plurality of pixel regions where the plurality of pixel electrodes 4 of the liquid crystal element 1 and the not-shown counter electrode face each other are filled with the pixel electrode. Substrate 2 from the initial homogeneous alignment state according to the voltage applied between
The orientation state is changed so as to rise with respect to three planes, and the birefringence of the liquid crystal layer and the polarization action of the polarizing plates 14 and 15 are reduced by the change in the birefringence of the liquid crystal layer according to the orientation state of the liquid crystal molecules. Controls the light transmittance, changes the display brightness of each pixel area, and displays an image.

In this embodiment, since the transmission axis 14a of the front polarizer 14 and the transmission axis 15a of the rear polarizer 15 are substantially orthogonal, the display brightness of the pixel area is
The Δn of the liquid crystal layer, which becomes brightest when the liquid crystal molecules are in the initial homogeneous alignment state, and changes as the liquid crystal molecules are aligned so as to rise with respect to the substrates 2 and 3.
The brightness changes according to the value of d.

Therefore, this liquid crystal display device has a voltage applied between the plurality of pixel electrodes 4 of the liquid crystal element 1 and the counter electrode, that is, data supplied to each pixel electrode 4 from the data line 12 via the TFT 5. The signal voltage may be controlled to drive the liquid crystal molecules from the initial homogeneous alignment state to the alignment state in which the display is darkest.

In this liquid crystal display device, since the initial alignment state of the liquid crystal molecules in the liquid crystal layer of the liquid crystal element 1 is a homogeneous alignment without twist, the viewing angle dependency of the transmittance is lower than that of the TN type liquid crystal display device. Few.

In this liquid crystal display device, as described above, the liquid crystal layer of the liquid crystal element 1 is configured such that the liquid crystal molecules of the nematic liquid crystal to which the chiral agent is added are uniformly homogeneously aligned in one direction. Therefore, in addition to the anchoring by the alignment film and the spontaneous cohesion of the nematic liquid crystal, the intermolecular force acting between the liquid crystal molecules by the chiral agent added to the liquid crystal acts on the liquid crystal molecules. I do.

Therefore, according to this liquid crystal display device, the stability of alignment of liquid crystal molecules is improved, and uniform homogeneous alignment in which directors of liquid crystal molecules are aligned in one direction can be obtained.
Then, even when the behavior of the liquid crystal molecules due to the electric field or the alignment state of the liquid crystal molecules is disturbed due to the bending deformation of the substrates 2 and 3 of the liquid crystal element 1, the director returns to the homogeneous alignment in which the directors are aligned in one direction thereafter. Therefore, there is no occurrence of alignment unevenness in the homogeneous alignment state of the liquid crystal molecules, and good display quality can be maintained.

In this liquid crystal display device, the chiral agent has a thickness d (μm) of the liquid crystal layer of the liquid crystal element 1 and a natural pitch p of the nematic liquid crystal to which the chiral agent is added.
(Μm) is added to the nematic liquid crystal in a range where the ratio d / p is less than 0.09. By setting the amount of the chiral agent in this range, the liquid crystal molecules can be homogeneously aligned without twisting the initial alignment state.

That is, the chiral agent added to the liquid crystal acts to twist-align the liquid crystal molecules. If the amount of the chiral agent is too large, the twisting force of the chiral agent is reduced by the alignment film. The liquid crystal molecules are twisted by overcoming the anchoring and the spontaneous aggregation of the nematic liquid crystal.

Whether the initial alignment state of the liquid crystal molecules is a homogeneous alignment in which the directors are aligned in one direction or a twist alignment depends on the anchoring strength of the alignment film, the spontaneous aggregation force of the nematic liquid crystal, and the chiral alignment. Thickness d (μm) of chiral nematic liquid crystal to which the agent is added
And the natural pitch p (μm) of the nematic liquid crystal is determined by the ratio d / p. When a general nematic liquid crystal is used, if the value of d / p is 0.09 or more, the initial value of the liquid crystal molecules is reduced. When the alignment state is twist alignment and d / p is less than 0.09, the liquid crystal molecules can obtain an initial alignment in a homogeneous alignment state in which the directors of the liquid crystal molecules are aligned in one direction according to the alignment treatment of the alignment film. In order to make the nematic liquid crystal more stable and to have a homogeneous alignment state in which directors are aligned in one direction, the value of d / p is 0.075.
It is desirable that:

For example, when the thickness d of the liquid crystal layer is 5 μm as in this embodiment, a liquid crystal material having a natural pitch p of 56 μm or more is used as a nematic liquid crystal to which a chiral agent is added. The liquid crystal layer thickness d is 5 μm, and the natural pitch p of the nematic liquid crystal to which the chiral agent is added is 56 μm.
In this case, d / p = 5/56 ≒ 0.089, and an initial alignment state in which liquid crystal molecules are aligned in a homogeneous state in which directors are aligned in one direction can be obtained.

On the other hand, the natural pitch p of the nematic liquid crystal to which the chiral agent is added is determined by the amount of the chiral agent added, and the force for twisting the nematic liquid crystal is determined by changing the amount of the chiral agent in the liquid crystal material to c ( Weight%), the reciprocal of the product of the natural pitch p of the nematic liquid crystal to which the chiral agent is added and the amount c of the chiral agent added, expressed by the twisting power defined by 1 / (p · c). You.

Therefore, the addition amount c of the chiral agent for obtaining a liquid crystal material having a natural pitch p of 56 μm is, for example, as follows when a chiral agent having a twisting power [1 / (p · c)] of 1.7 is used. = 1 / (1.7 × 56) × 10
0 ≒ 1.50 (% by weight), and the chiral agent was used in 1.
By adding at a ratio of 50 (% by weight) or less, a liquid crystal material having a natural pitch p of 56 μm or more can be obtained.

Note that the amount of the chiral agent added is
/ P is more preferably less than 0.075. By doing so, the initial alignment state of the liquid crystal molecules can be made a homogeneous alignment with better stability.

That is, for example, when the thickness d of the liquid crystal layer is 5 μm
In the case of (1), it is more preferable to use a liquid crystal material having a natural pitch p of 67 μm or more as the nematic liquid crystal to which the chiral agent is added. The liquid crystal layer thickness d is 5 μm, and the natural pitch of the nematic liquid crystal to which the chiral agent is added. p is 6
At 7 μm, d / p = 5/67 ≒ 0.075,
A more stable homogeneous orientation can be obtained.

In the liquid crystal display device of the above embodiment, the surface light source 17 is provided behind the rear polarizing plate 15 provided on the rear surface of the liquid crystal element 1, and the transflective light is provided on the front surface of the surface light source 17. A reflection / illumination means 16 comprising a film 18 is disposed, and a semi-transmissive reflection film comprising a rough deposited film of aluminum or the like or a plated film is formed on the inner surface of the rear substrate 3 of the liquid crystal element 1. Even if only the surface light source 17 is arranged behind the rear polarizing plate 15, a reflective display using external light,
Transmissive display using illumination light from behind can be performed.

When a transflective film is formed on the inner surface of the rear substrate 3 of the liquid crystal element 1, the transflective film is formed on the rear substrate 3, and the transflective film is formed of a transparent insulating film. And a TFT 5, a gate line 11, a compensation capacitor electrode 13, a data line 12, and a pixel electrode 4 may be formed thereon, and a semi-transmissive reflective film is formed on each of the plurality of pixel electrodes 4. May be.

The liquid crystal element 1 used in the above embodiment is
An active matrix liquid crystal element using a TFT as an active element. If the liquid crystal element has a liquid crystal layer in which liquid crystal molecules of nematic liquid crystal to which a chiral agent is added are homogeneously aligned, for example, a two-terminal non-terminal such as MIM is used. An active matrix liquid crystal element having a linear resistance element as an active element, a simple matrix liquid crystal element, or a segment type liquid crystal element may be used.

Further, the liquid crystal display device of the above embodiment is of a reflection / transmission type which performs a reflection display using external light and a transmissive display using illumination light from behind. The present invention can be applied to a reflective liquid crystal display device that always performs reflective display using external light and a transmissive liquid crystal display device that always performs transmissive display using illumination light.

When the present invention is applied to a reflection type liquid crystal display device, a polarizing plate is disposed only on the front side of the liquid crystal element, and a reflection film is formed on the outer or inner surface of the rear substrate of the liquid crystal element. The light incident on the liquid crystal display device from its front surface and transmitted through the polarizing plate and the liquid crystal layer of the liquid crystal display element is reflected by the reflective film, and of the reflected light, the light transmitted through the polarizing plate is used as image light. The light may be emitted to the front.

Further, in the liquid crystal display device of this embodiment, a phase plate for compensating optical characteristics may be disposed between the liquid crystal element and the polarizing plate disposed on the front side. In this case, it is preferable to dispose two phase plates, one having an optical axis in the plane and the other having an optical axis in the thickness direction. The phase plate having an optical axis in the plane enables white display by compensating the coloring of transmitted light of the above-mentioned homogeneous type liquid crystal element, and the phase plate having an optical axis in the thickness direction is the homogeneous type. The viewing angle dependence of the transmittance of the liquid crystal element is further improved. The homogeneous type liquid crystal element of this embodiment has a phase plate composed of a uniaxially stretched film or the like or a phase plate composed of a film in which the major axes of polymers are arranged in the thickness direction because liquid crystal molecules are not twisted. In addition, it is easy to compensate for the phase difference of the transmitted light due to the alignment state of the liquid crystal molecules, and a liquid crystal display device having a wide viewing angle characteristic in which the optical characteristics are sufficiently compensated for by the phase plate is obtained.

[0056]

According to the present invention, the liquid crystal layer of the liquid crystal element has a configuration in which liquid crystal molecules of a nematic liquid crystal to which a chiral agent is added have a uniform homogeneous alignment in which directors are arranged in one direction. Therefore, it is possible to prevent alignment unevenness in the homogeneous alignment state of the liquid crystal molecules, and to maintain good display quality.

In the liquid crystal display device according to the present invention, the amount of the chiral agent is determined by the thickness d of the liquid crystal layer of the liquid crystal element.
The ratio d / p between (μm) and the natural pitch p (μm) of the nematic liquid crystal to which the chiral agent has been added may be an amount that is less than 0.09. Thereby, it is possible to obtain a uniform homogeneous alignment initial alignment state in which the directors are aligned in one direction without twisting the liquid crystal molecules.

[0058] The amount of the chiral agent added is d / p
Is more preferably 0.075 or less,
This makes it possible to set the initial alignment state of the liquid crystal molecules to a homogeneous alignment with higher stability.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a part of a liquid crystal display device according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Liquid crystal element 2, 3 ... Substrate 2a, 3a ... Alignment processing direction 4 ... Pixel electrode 5 ... TFT 11 ... Gate line 12 ... Data line 13 ... Compensation capacitance electrode 14, 15 ... Polarizer 14a, 15a ... Transmission axis 16 ... Reflection / illumination means 17: Surface light source 18: Transflective reflection film

Claims (3)

[Claims] 1. A pair of substrates each having an electrode and an alignment film covering the electrodes formed on opposing inner surfaces, and liquid crystal molecules of a nematic liquid crystal sealed between the pair of substrates and added with a chiral agent. A liquid crystal display device comprising: a liquid crystal layer that is homogeneously aligned along one direction; and a polarizing plate that is disposed on at least a display observation side of the pair of substrates. 2. The liquid crystal layer has a thickness d (μm) and a natural pitch p (μm) of a nematic liquid crystal to which a chiral agent is added.
The liquid crystal display device according to claim 1, comprising a nematic liquid crystal to which a chiral agent is added in an amount such that a ratio d / p to m) is less than 0.09. 3. The liquid crystal layer has a thickness d (μm) and a natural pitch p (μm) of a nematic liquid crystal to which a chiral agent is added.
2. The liquid crystal display device according to claim 1, comprising a nematic liquid crystal to which a chiral agent is added in an amount such that a ratio d / p to m) is 0.075 or less.